Surgical instruments and surgical methods, as well as methods of chemotherapy, and methods of, and instruments for, radiation therapy and hyperthermic treatment are known for the medical treatment of proliferating tissue, although methods of acoustic surgery for that purpose have not presently been widely accepted in clinical practice.
For acoustic surgery, a mechanically oscillated hollow metal pin, for example, is used as a therapeutic tool. Such an instrument is described for example, in DE-A-35 27 586, and analogous devices for the removal of tissue by ultrasonic surgery are disclosed in U.S. Pat. No. 3,526,219 and U.S. Pat. No. 3,589,363. The attainments of such mechano-acoustic methods, however, extend from the reversible scrambling of the cell contents to the disintegration to a great extent of membranes, mitochondria and cell nuclei.
Ultrasonic instruments and methods acting hyperthermically are known, for example, from DE-A-33 31 510, DE-A-33 00 121 and DE-A31 50 513. Nevertheless, these non-surgical instruments and methods, for the treatment of tissues, in particular proliferating tissues, in human beings and animals must presently be regarded as experimental. This is also the case in respect of the non-surgical acoustic systems which do not operate hyperthermically, for the treatment of proliferating tissues in human bodies. Treatment by means of a hyperthermically operating device is based upon the appreciation that tumors are killed at a temperature of say 42.5.degree. C. when maintained for a protracted period. Raising the temperature locally within the body presents difficulties, however, since the tissue is cooled by the perfusion of blood and comparatively protracted high sonic intensities are needed to bring about a substantial temperature rise. These high sonic intensities may, however, cause cavitations in, and consequential injury to, healthy tissue in front of the tumor.
But little information has been published in the field relating to methods of treating proliferating tissues, which are non-surgical and acoustic and do not act hyperthermically.
DE-A-35 44 344, for example, discloses a device for inhibiting the growth of new pathological forms in living organisms, in which blood vessels are thrombosed by means of focussed shock waves, a once-only positive pressure pulse being generated for this purpose. The following effects of shock waves on tissues are disclosed in the publication "Prog.app.Microcirc.", vol.12, pages 41 to 50, 1987: vasoconstriction, stasis in capillaries, microhaemorrhages, the emergence of macromolecules from venules, the formation of conglomerates in venules, haemorrhages and the formation of haematoma, the destruction of vascular walls, the destruction of lining cells and the issue of red blood cells from blood vessels. This publication is silent, however, as to the treatment of tumors.
During the 64th convention of Bavarian Surgeons in July 1987 at Bad Reichenhall, Wilmer, Delius and Brendel reported on the effect of shock waves on tumorous cells in vitro, with reference to the so-called "ratio of adoption". At the same venue, Goetz, Konigsberger, Conzen and Brendel reported on the effect of shock waves on tumor microcirculation and tumor growth in the case of Syrian golden hamsters. There were reports upon the following effects: microhaemorrhages, extravasation of macromolecules, intravascular thrombosing actions and temporary arteriole constrictions. Tumor colliquations were obtained by a repetitive treatment by means of series of shock waves.